US7264318B2 - Brake pressure control arrangement - Google Patents

Brake pressure control arrangement Download PDF

Info

Publication number
US7264318B2
US7264318B2 US11/043,698 US4369805A US7264318B2 US 7264318 B2 US7264318 B2 US 7264318B2 US 4369805 A US4369805 A US 4369805A US 7264318 B2 US7264318 B2 US 7264318B2
Authority
US
United States
Prior art keywords
unit
pressure
pump
hydraulic
actuating
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Fee Related, expires
Application number
US11/043,698
Other versions
US20050258684A1 (en
Inventor
Andreas Herp
Michael Schopfer
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Mercedes Benz Group AG
Original Assignee
DaimlerChrysler AG
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by DaimlerChrysler AG filed Critical DaimlerChrysler AG
Assigned to DALMLERCHRYSLER AG reassignment DALMLERCHRYSLER AG ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: HERP, ANDREAS, SCHOPPER, MICHAEL
Publication of US20050258684A1 publication Critical patent/US20050258684A1/en
Application granted granted Critical
Publication of US7264318B2 publication Critical patent/US7264318B2/en
Assigned to DAIMLER AG reassignment DAIMLER AG CHANGE OF NAME (SEE DOCUMENT FOR DETAILS). Assignors: DAIMLERCHRYSLER AG
Adjusted expiration legal-status Critical
Expired - Fee Related legal-status Critical Current

Links

Images

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60T—VEHICLE BRAKE CONTROL SYSTEMS OR PARTS THEREOF; BRAKE CONTROL SYSTEMS OR PARTS THEREOF, IN GENERAL; ARRANGEMENT OF BRAKING ELEMENTS ON VEHICLES IN GENERAL; PORTABLE DEVICES FOR PREVENTING UNWANTED MOVEMENT OF VEHICLES; VEHICLE MODIFICATIONS TO FACILITATE COOLING OF BRAKES
    • B60T8/00—Arrangements for adjusting wheel-braking force to meet varying vehicular or ground-surface conditions, e.g. limiting or varying distribution of braking force
    • B60T8/32—Arrangements for adjusting wheel-braking force to meet varying vehicular or ground-surface conditions, e.g. limiting or varying distribution of braking force responsive to a speed condition, e.g. acceleration or deceleration
    • B60T8/34—Arrangements for adjusting wheel-braking force to meet varying vehicular or ground-surface conditions, e.g. limiting or varying distribution of braking force responsive to a speed condition, e.g. acceleration or deceleration having a fluid pressure regulator responsive to a speed condition
    • B60T8/44—Arrangements for adjusting wheel-braking force to meet varying vehicular or ground-surface conditions, e.g. limiting or varying distribution of braking force responsive to a speed condition, e.g. acceleration or deceleration having a fluid pressure regulator responsive to a speed condition co-operating with a power-assist booster means associated with a master cylinder for controlling the release and reapplication of brake pressure through an interaction with the power assist device, i.e. open systems
    • B60T8/441—Arrangements for adjusting wheel-braking force to meet varying vehicular or ground-surface conditions, e.g. limiting or varying distribution of braking force responsive to a speed condition, e.g. acceleration or deceleration having a fluid pressure regulator responsive to a speed condition co-operating with a power-assist booster means associated with a master cylinder for controlling the release and reapplication of brake pressure through an interaction with the power assist device, i.e. open systems using hydraulic boosters
    • B60T8/442—Arrangements for adjusting wheel-braking force to meet varying vehicular or ground-surface conditions, e.g. limiting or varying distribution of braking force responsive to a speed condition, e.g. acceleration or deceleration having a fluid pressure regulator responsive to a speed condition co-operating with a power-assist booster means associated with a master cylinder for controlling the release and reapplication of brake pressure through an interaction with the power assist device, i.e. open systems using hydraulic boosters the booster being a fluid return pump, e.g. in combination with a brake pedal force booster
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60T—VEHICLE BRAKE CONTROL SYSTEMS OR PARTS THEREOF; BRAKE CONTROL SYSTEMS OR PARTS THEREOF, IN GENERAL; ARRANGEMENT OF BRAKING ELEMENTS ON VEHICLES IN GENERAL; PORTABLE DEVICES FOR PREVENTING UNWANTED MOVEMENT OF VEHICLES; VEHICLE MODIFICATIONS TO FACILITATE COOLING OF BRAKES
    • B60T8/00—Arrangements for adjusting wheel-braking force to meet varying vehicular or ground-surface conditions, e.g. limiting or varying distribution of braking force
    • B60T8/32—Arrangements for adjusting wheel-braking force to meet varying vehicular or ground-surface conditions, e.g. limiting or varying distribution of braking force responsive to a speed condition, e.g. acceleration or deceleration
    • B60T8/34—Arrangements for adjusting wheel-braking force to meet varying vehicular or ground-surface conditions, e.g. limiting or varying distribution of braking force responsive to a speed condition, e.g. acceleration or deceleration having a fluid pressure regulator responsive to a speed condition
    • B60T8/36—Arrangements for adjusting wheel-braking force to meet varying vehicular or ground-surface conditions, e.g. limiting or varying distribution of braking force responsive to a speed condition, e.g. acceleration or deceleration having a fluid pressure regulator responsive to a speed condition including a pilot valve responding to an electromagnetic force
    • B60T8/3615—Electromagnetic valves specially adapted for anti-lock brake and traction control systems
    • B60T8/3655—Continuously controlled electromagnetic valves
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60T—VEHICLE BRAKE CONTROL SYSTEMS OR PARTS THEREOF; BRAKE CONTROL SYSTEMS OR PARTS THEREOF, IN GENERAL; ARRANGEMENT OF BRAKING ELEMENTS ON VEHICLES IN GENERAL; PORTABLE DEVICES FOR PREVENTING UNWANTED MOVEMENT OF VEHICLES; VEHICLE MODIFICATIONS TO FACILITATE COOLING OF BRAKES
    • B60T8/00—Arrangements for adjusting wheel-braking force to meet varying vehicular or ground-surface conditions, e.g. limiting or varying distribution of braking force
    • B60T8/32—Arrangements for adjusting wheel-braking force to meet varying vehicular or ground-surface conditions, e.g. limiting or varying distribution of braking force responsive to a speed condition, e.g. acceleration or deceleration
    • B60T8/34—Arrangements for adjusting wheel-braking force to meet varying vehicular or ground-surface conditions, e.g. limiting or varying distribution of braking force responsive to a speed condition, e.g. acceleration or deceleration having a fluid pressure regulator responsive to a speed condition
    • B60T8/40—Arrangements for adjusting wheel-braking force to meet varying vehicular or ground-surface conditions, e.g. limiting or varying distribution of braking force responsive to a speed condition, e.g. acceleration or deceleration having a fluid pressure regulator responsive to a speed condition comprising an additional fluid circuit including fluid pressurising means for modifying the pressure of the braking fluid, e.g. including wheel driven pumps for detecting a speed condition, or pumps which are controlled by means independent of the braking system
    • B60T8/404—Control of the pump unit
    • B60T8/4059—Control of the pump unit involving the rate of delivery
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60T—VEHICLE BRAKE CONTROL SYSTEMS OR PARTS THEREOF; BRAKE CONTROL SYSTEMS OR PARTS THEREOF, IN GENERAL; ARRANGEMENT OF BRAKING ELEMENTS ON VEHICLES IN GENERAL; PORTABLE DEVICES FOR PREVENTING UNWANTED MOVEMENT OF VEHICLES; VEHICLE MODIFICATIONS TO FACILITATE COOLING OF BRAKES
    • B60T8/00—Arrangements for adjusting wheel-braking force to meet varying vehicular or ground-surface conditions, e.g. limiting or varying distribution of braking force
    • B60T8/32—Arrangements for adjusting wheel-braking force to meet varying vehicular or ground-surface conditions, e.g. limiting or varying distribution of braking force responsive to a speed condition, e.g. acceleration or deceleration
    • B60T8/34—Arrangements for adjusting wheel-braking force to meet varying vehicular or ground-surface conditions, e.g. limiting or varying distribution of braking force responsive to a speed condition, e.g. acceleration or deceleration having a fluid pressure regulator responsive to a speed condition
    • B60T8/48—Arrangements for adjusting wheel-braking force to meet varying vehicular or ground-surface conditions, e.g. limiting or varying distribution of braking force responsive to a speed condition, e.g. acceleration or deceleration having a fluid pressure regulator responsive to a speed condition connecting the brake actuator to an alternative or additional source of fluid pressure, e.g. traction control systems
    • B60T8/4809—Traction control, stability control, using both the wheel brakes and other automatic braking systems
    • B60T8/4827—Traction control, stability control, using both the wheel brakes and other automatic braking systems in hydraulic brake systems
    • B60T8/4863—Traction control, stability control, using both the wheel brakes and other automatic braking systems in hydraulic brake systems closed systems
    • B60T8/4872—Traction control, stability control, using both the wheel brakes and other automatic braking systems in hydraulic brake systems closed systems pump-back systems

Definitions

  • the invention relates to a brake pressure control arrangement with an ABS and/or an ESP function for operating the brakes of a motor vehicle including pump units serving as boosters for the ABS and ESP functions and for the driver-initiated braking.
  • the arrangement comprises a hydraulic actuating device and a hydraulic receiver unit which is in communication with the hydraulic actuating device for operating the wheel brakes of the motor vehicle, and at least one pump unit which, by means of an automatic control device and control valves operated thereby, can be placed, when the hydraulic actuating device is actuated, in intervals into a first effective operating state wherein the receiver unit is, for pressure release, in communication with the suction side of the pump unit and into a normal operating state, wherein the receiver unit is in communication with the pressure side of the pump unit while the suction side of the pump unit is connected to the hydraulic actuating device.
  • the hydraulic pressure at the hydraulic receiver is determined by the hydraulic fluid volume supplied to the hydraulic receiver unit, and a suction flow control valve is arranged between the actuating device and the pump and controlled by an automatic brake control arrangement.
  • Such a braking pressure control arrangement is the subject of DE 199 39 437 A1.
  • This braking pressure control arrangement makes it possible with the use of a pump unit to provide for the receiver units hydraulic pressures which are substantially higher than the pressures generated by the hydraulic actuating device, that is, the pump is used as a pressure amplifier.
  • the first pump-effective operating state serves to rapidly reduce the pressure at a hydraulic receiver if a wheel blocks during a braking procedure, so that the wheel is again rotated and can transmit correspondingly higher side guide forces.
  • the first pump-effective operating state is consequently mainly used for the anti-blocking control of vehicle wheels.
  • a drive wheel slip control can be provided.
  • the pump unit can be controlled at intervals, when the actuating device is not operated in a second pump-effective state wherein the hydraulic receiver units are placed in communication with the pressure side of the pump unit. A spinning wheel can, in this way, be braked down.
  • DE 199 39 437 A1 discloses a brake pressure control arrangement wherein a pressure limit valve is arranged between the pressure side of the pump unit and the hydraulic actuating device, which pressure limit valve is controlled by a piston arrangement depending on the pressure provided by the hydraulic actuating device, that is, the hydraulic actuating device pressure determines the maximum pressure provided at the pressure side pump unit.
  • the pressure limiting valve must be arranged in series with a shut-off valve which is operated by the control arrangement if the driving wheel slip control mentioned earlier is to be ensured.
  • the shut-off valve is automatically closed, so that, at the receiver units or, respectively, the pressure side of the pump unit, a high pressure can be provided although the pressure limit valve has only a very small opening pressure when the actuating unit is not operated that is the pressure supplied by the actuating unit is very small.
  • DE 197 56 248 A1 discloses for example a brake pressure control system wherein the vacuum generated in the internal combustion engine of a motor vehicle is utilized for generating the auxiliary forces. This arrangement also permits the generation of high hydraulic pressures for actuating the vehicle brakes with comparably small actuating forces applied by an operator.
  • the actuating unit includes a stepped piston which, with a first piston area is disposed in a first operating cylinder and with a second piston area is disposed in a second cylinder for the displacement of the hydraulic fluid therein.
  • Both cylinders are in communication in parallel with respective receiver units of the wheel brakes (wheel cylinders) wherein a pump can be provided in the communication lines between the two cylinders in such a way that the pressure in one of the cylinders can be reduced.
  • the actuating force applied by the operator is mainly effective as a high pressure in the other cylinder, that is, the actuating force is transmitted to a relatively small piston area so that a relatively high hydraulic pressure is generated in the receiver units generating a high brake force.
  • the pressure of the hydraulic fluid supplied to the receiver units depends on the hydraulic fluid volume supplied to the receiver units by controlling the intake flow control valve for the admission of hydraulic fluid to the pump and, in other operating states, the pump and valves are operated to alternately supply hydraulic fluid to, and receive hydraulic fluid from, the receiver units.
  • the pressure limit valve provided in DE 199 39 437 A1 and the piston arrangement for the control thereof which is controlled by the pressure provided by the hydraulic actuating device and the pressure at the pressure side of the pump unit, is not needed. Instead, the pressure is limited by a valve which is operated by the control arrangement with the result that the control arrangement alone determines the maximum pressure at the pressure side of the pump unit. In this way, the behavior of the control arrangement is particularly accurate and reproducible.
  • control arrangement must only be in a position to control the pump unit depending on the operating parameters of the actuating device for example deciding on the control stroke of the actuating device or the hydraulic pressure generated by the actuating device.
  • the suction flow control valve may be in the form of an over-pressure valve subjected to the opposite hydraulic pressure in opening direction.
  • a controllable over-pressure valve controls the supply flow from the pump unit like a suction throttle and, consequently, the achievable hydraulic pressure at the pressure side of the pump unit, that is, the receiver side hydraulic pressure and, accordingly, the brake forces for the wheel brakes.
  • FIG. 1 shows a brake pressure control arrangement in accordance with the invention
  • FIG. 2 shows a diagram of the control behavior of the arrangement.
  • the brake pressure control arrangement includes, in a basically known manner, a hydraulic actuating device 2 with a brake pedal 1 , the hydraulic actuating device 2 being a two-circuit device.
  • the hydraulic actuating device 2 includes a housing with a cylinder in which two pistons 3 and 4 are serially arranged, one after the other.
  • the piston 3 is mechanically coupled to the brake pedal 1 .
  • the piston 4 is a floating piston, which is supported at its front end by a compression spring 6 on the front end wall of the cylinder and, at its opposite side by a compression spring 5 on the front end of the piston 3 .
  • the springs 6 and 5 bias the pistons 4 on 3 and, accordingly, the pedal 1 in a rest position in which a hydraulic fluid reservoir 7 disposed on the actuating device 2 is in communication, via bores 8 and 9 , with the piston operating chambers 10 and 11 shown in FIG. 1 axially at the left front ends of the pistons 3 and 4 .
  • Each piston operating chamber includes an outlet 12 and respectively 13 , which is shown in FIG. 1 displaced to the left with respect to the bores 8 and, respectively, 9 .
  • communication lines 14 and 14 ′ Connected to the outlets 12 and 13 are communication lines 14 and 14 ′ by way of which the piston operating chambers 10 and 11 are in communication with the receiver units 15 and 15 ′ (wheel cylinders) of the front wheel brakes 16 and the rear wheel brakes 16 ′ of the vehicle.
  • Each communication line 14 or, respectively, 14 ′ is connected to a line 18 or, respectively 18 ′ by way of a normally open shut-off valve 17 , or respectively 17′, and the lines 18 , 18 ′ are connected via normally open shut off valves 19 , 19 ′ to the receiver units 15 and 15 ′ respectively.
  • connecting lines 14 , 14 ′ are connected by way of normally closed shut off valves 20 , 20 ′ to the lines 21 and respectively 21′, which are in communication, by way of normally closed shut off valves 22 , 22 ′ that are arranged parallel to the valve 19 and, respectively, 19 ′, with the receiver units 15 and, respectively, 15 ′.
  • the lines 21 , 21 ′ include one-way valves 23 , 23 ′ which permit only a hydraulic fluid return flow from the receiver units 15 and respectively 15 ′ when the valves 22 and 22 ′ are open.
  • pumps 25 and respectively 25 ′ driven by electric motors 25 and, respectively, 25 ′ are arranged together with check valves 26 and respectively, 26 ′ in such a way that hydraulic fluid can only flow from the line 21 or respectively 21′ to the line 18 or respectively 18 ′.
  • controllable over-pressure valves 27 and respectively 27 ′ with serially arranged check valves 28 , 28 ′ are provided such that, with the respective over-pressure valves 27 , 27 ′ opened, hydraulic fluid flow is possible only from the line 14 or, respectively, 14 ′ to the line 21 or, respectively, 21 ′.
  • All the above control valves are operated by an electronic control unit 29 .
  • the electronic control unit 29 is connected to a travel distance sensor 30 for determining the actuating position of the brake pedal 1 and/or the pressure sensors 31 for determining a characteristic hydraulic fluid pressure at the output side of the hydraulic actuating unit 2 .
  • control unit 29 is connected to wheel sensors of the vehicle which however are not shown but which provide information concerning wheel speed or wheel blockage conditions for the respective wheels.
  • the system as shown in FIG. 1 operates as follows:
  • valves If a fault is detected in the system by the control unit 29 which constantly checks itself for faults, all valves assume the switch positions as shown in FIG. 1 and the electric motors 24 and 24 ′ of the pumps 25 and 25 ′ are de-energized. However, this state of the valves and the electric motors may also be present when the brakes 16 and, respectively, 16 ′ are expected to provide only comparatively small brake forces.
  • the pistons 3 and 4 are moved beyond the bores 8 and 9 , so that the piston operating chambers 10 and 11 are disconnected from the reservoir 7 and, upon further actuation of the brake pedal 1 , hydraulic fluid is directed from the piston operating chambers 10 and 11 into the lines 14 and 14 ′, respectively of the wheel brakes 16 and 16 ′ and the brakes are actuated to brake the wheels.
  • the pistons 3 and 4 and the brake pedal 1 are returned by the springs 5 and 6 to their rest positions in which the receiver unit 15 and 15 ′ in the switch positions of the valves as shown are in communication with the reservoir 7 and consequently not under pressure. No brake effect is therefore present at the wheel brakes 16 and, respectively 16 ′.
  • shutoff valves 17 , 17 ′ are closed when the brake pedal 1 is actuated. Further, the valves 19 , 20 and 22 or, respectively, the valves 19 ′, 20 ′, and 22 ′ are in the positions shown in FIG. 1 .
  • the over-pressure valves 27 and 27 ′ are controlled by the control unit 29 depending on the signals of the travel distance sensor 30 and/or the pressure sensor 31 , such that, with predetermined controllable pressures in the lines 14 and, respectively, 14 ′, they are opened and the pumps 25 , and respectively, 25 ′ suck in a certain hydraulic fluid volume by way of the over-pressure valves 27 and, respectively, 27 ′ from the communication lines 14 and respectively 14 ′ and supply it, by way of the valves 19 and respectively 27 ′, from the communication lines 14 and respectively 14 ′ by way of the valves 19 and respectively 19 ′ to the receiver units 15 and, respectively 15 ′ of the wheel brakes 16 and, respectively, 16 ′ and there, generate a hydraulic pressure depending on the amount of the hydraulic fluid supplied.
  • This hydraulic pressure at the receiver side may be substantially above the hydraulic fluid pressure in the communication lines 14 and, respectively, 14 ′.
  • the hydraulic fluid volume which is supplied by the pumps 25 , 25 ′ to the receiver units 15 and 15 ′ and which determines the hydraulic pressure therein is determined by the overpressure valves 27 , and respectively, 27 ′ whose opening behavior is controlled by the control unit 29 .
  • the over-pressure valves 27 and 27 ′ act with respect to the pump 25 and 25 ′ like intake throttles.
  • valves 22 and 20 and respectively 22 ′ and 20 ′ are opened so that the hydraulic fluid can flow back from the receiver units 15 and, respectively, 15 ′ to the actuating unit 2 , wherein possible pressure pulses are attenuated by hydraulic pulsation dampers 32 , and respectively, 32 ′, which are in communication with the outlet side of the valves 22 and respectively 22 ′.
  • the pump 25 and respectively 25 ′ may be constantly energized if, with the brake pedal 1 not actuated, the valves 19 and 22 and, respectively, 19 ′ and 22 ′ and/or the valves 17 and 20 , and respectively, 17 ′ and 20 ′ are constantly open and, accordingly permit hydraulic fluid circulation by the pump 25 and 25 ′.
  • the control unit 29 can selectively open the valves 22 and, respectively, 22 ′ and, at the same time, the valves 17 and respectively 17 ′ so that the pump 25 and respectively 25 ′, can pump hydraulic fluid from the receiver unit 15 , 15 ′ associated with the open valves 22 , 22 ′ back to the actuating unit 2 .
  • the valves 22 and 17 , and, respectively, 22 ′ and 17 ′ are opened in intervals in order to release the respective blocked wheel in intervals in order to then again be able to effectively brake the wheel.
  • FIG. 2 shows the operational behavior of the brake pressure control arrangement according to the invention.
  • a comparatively large brake pedal force F 2 is required in order to achieve a pedal stroke S 0 or the discharge of a hydraulic fluid volume V 0 from the actuating unit or, respectively, to achieve a hydraulic pressure P 0 in the receivers.
  • the pumps 25 and respectively 25 ′ assist the transport of hydraulic fluid from the actuating unit 2 to the receiver units 15 , 15 ′ upon actuation of the brake pedal 1 , so that a pedal force of only F 1 is required to achieve the stroke S 0 , the receiver unit pressure P 0 or, respectively, a displacement movement of the hydraulic volume V 0 to the receiver units 15 and 15 ′ respectively.
  • the curve K s shows the functional relationship in an exemplary way.

Landscapes

  • Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Fluid Mechanics (AREA)
  • Transportation (AREA)
  • Mechanical Engineering (AREA)
  • Electromagnetism (AREA)
  • Regulating Braking Force (AREA)

Abstract

In a method for joining at least two work pieces by friction stir welding wherein the work pieces are placed placed in overlapping relationship and are at least partially plasticized in the area where they are to be joined by a rotating friction tool provided with a pin-like projection which is moved axially into the area of the joint to be formed, the projection on the rotating tool has a length corresponding about to the thickness of the upper work piece and a shoulder around the pin-like projection so that, upon movement of the tool toward the work pieces, the work piece material is plasticized by the rotating pin-like projection which moves axially into the work piece material until it reaches the surfaces of the lowermost workpiece.

Description

This is a Continuation-In-Part Application of International Application PCT/EP2003/007548 filed Jul. 11, 2003 and claiming the priority of German application 102 34 366.7 filed Jul. 27, 2002.
BACKGROUND OF THE INVENTION
The invention relates to a brake pressure control arrangement with an ABS and/or an ESP function for operating the brakes of a motor vehicle including pump units serving as boosters for the ABS and ESP functions and for the driver-initiated braking.
The arrangement comprises a hydraulic actuating device and a hydraulic receiver unit which is in communication with the hydraulic actuating device for operating the wheel brakes of the motor vehicle, and at least one pump unit which, by means of an automatic control device and control valves operated thereby, can be placed, when the hydraulic actuating device is actuated, in intervals into a first effective operating state wherein the receiver unit is, for pressure release, in communication with the suction side of the pump unit and into a normal operating state, wherein the receiver unit is in communication with the pressure side of the pump unit while the suction side of the pump unit is connected to the hydraulic actuating device. The hydraulic pressure at the hydraulic receiver is determined by the hydraulic fluid volume supplied to the hydraulic receiver unit, and a suction flow control valve is arranged between the actuating device and the pump and controlled by an automatic brake control arrangement.
Such a braking pressure control arrangement is the subject of DE 199 39 437 A1. This braking pressure control arrangement makes it possible with the use of a pump unit to provide for the receiver units hydraulic pressures which are substantially higher than the pressures generated by the hydraulic actuating device, that is, the pump is used as a pressure amplifier.
The first pump-effective operating state serves to rapidly reduce the pressure at a hydraulic receiver if a wheel blocks during a braking procedure, so that the wheel is again rotated and can transmit correspondingly higher side guide forces. The first pump-effective operating state is consequently mainly used for the anti-blocking control of vehicle wheels.
Furthermore, with the brake pressure control arrangement according to DE 199 39 437 A1 also a drive wheel slip control can be provided. In this case, the pump unit can be controlled at intervals, when the actuating device is not operated in a second pump-effective state wherein the hydraulic receiver units are placed in communication with the pressure side of the pump unit. A spinning wheel can, in this way, be braked down.
DE 199 39 437 A1 discloses a brake pressure control arrangement wherein a pressure limit valve is arranged between the pressure side of the pump unit and the hydraulic actuating device, which pressure limit valve is controlled by a piston arrangement depending on the pressure provided by the hydraulic actuating device, that is, the hydraulic actuating device pressure determines the maximum pressure provided at the pressure side pump unit.
For this reason, the pressure limiting valve must be arranged in series with a shut-off valve which is operated by the control arrangement if the driving wheel slip control mentioned earlier is to be ensured. During driving wheel slip control the shut-off valve is automatically closed, so that, at the receiver units or, respectively, the pressure side of the pump unit, a high pressure can be provided although the pressure limit valve has only a very small opening pressure when the actuating unit is not operated that is the pressure supplied by the actuating unit is very small.
DE 197 56 248 A1 discloses for example a brake pressure control system wherein the vacuum generated in the internal combustion engine of a motor vehicle is utilized for generating the auxiliary forces. This arrangement also permits the generation of high hydraulic pressures for actuating the vehicle brakes with comparably small actuating forces applied by an operator.
DE 197 16 404 C1 discloses another possibility to generate at the receiver units a hydraulic pressure which is high in comparison with the operating force applied at the actuating unit. In accordance with this publication, the actuating unit includes a stepped piston which, with a first piston area is disposed in a first operating cylinder and with a second piston area is disposed in a second cylinder for the displacement of the hydraulic fluid therein. Both cylinders are in communication in parallel with respective receiver units of the wheel brakes (wheel cylinders) wherein a pump can be provided in the communication lines between the two cylinders in such a way that the pressure in one of the cylinders can be reduced. In this way, the actuating force applied by the operator is mainly effective as a high pressure in the other cylinder, that is, the actuating force is transmitted to a relatively small piston area so that a relatively high hydraulic pressure is generated in the receiver units generating a high brake force.
It is the object of the present invention to provide a brake pressure system of the type initially described however of a more simple design.
SUMMARY OF THE INVENTION
In a brake pressure control arrangement with at least one of an ABS function and an ESP function wherein pump units are provided as pressure boosters, the pressure of the hydraulic fluid supplied to the receiver units depends on the hydraulic fluid volume supplied to the receiver units by controlling the intake flow control valve for the admission of hydraulic fluid to the pump and, in other operating states, the pump and valves are operated to alternately supply hydraulic fluid to, and receive hydraulic fluid from, the receiver units.
With the arrangement according to the present invention, the pressure limit valve provided in DE 199 39 437 A1 and the piston arrangement for the control thereof, which is controlled by the pressure provided by the hydraulic actuating device and the pressure at the pressure side of the pump unit, is not needed. Instead, the pressure is limited by a valve which is operated by the control arrangement with the result that the control arrangement alone determines the maximum pressure at the pressure side of the pump unit. In this way, the behavior of the control arrangement is particularly accurate and reproducible.
Essentially, the control arrangement must only be in a position to control the pump unit depending on the operating parameters of the actuating device for example deciding on the control stroke of the actuating device or the hydraulic pressure generated by the actuating device.
In a particularly advantageous embodiment, the suction flow control valve may be in the form of an over-pressure valve subjected to the opposite hydraulic pressure in opening direction. Such a controllable over-pressure valve controls the supply flow from the pump unit like a suction throttle and, consequently, the achievable hydraulic pressure at the pressure side of the pump unit, that is, the receiver side hydraulic pressure and, accordingly, the brake forces for the wheel brakes.
The invention will be described below in greater detail on the basis of the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 shows a brake pressure control arrangement in accordance with the invention, and
FIG. 2 shows a diagram of the control behavior of the arrangement.
 DESCRIPTION OF A PREFERRED EMBODIMENT
As shown in FIG. 1, the brake pressure control arrangement includes, in a basically known manner, a hydraulic actuating device 2 with a brake pedal 1, the hydraulic actuating device 2 being a two-circuit device. The hydraulic actuating device 2 includes a housing with a cylinder in which two pistons 3 and 4 are serially arranged, one after the other. The piston 3 is mechanically coupled to the brake pedal 1. The piston 4 is a floating piston, which is supported at its front end by a compression spring 6 on the front end wall of the cylinder and, at its opposite side by a compression spring 5 on the front end of the piston 3. The springs 6 and 5 bias the pistons 4 on 3 and, accordingly, the pedal 1 in a rest position in which a hydraulic fluid reservoir 7 disposed on the actuating device 2 is in communication, via bores 8 and 9, with the piston operating chambers 10 and 11 shown in FIG. 1 axially at the left front ends of the pistons 3 and 4. Each piston operating chamber includes an outlet 12 and respectively 13, which is shown in FIG. 1 displaced to the left with respect to the bores 8 and, respectively, 9.
Connected to the outlets 12 and 13 are communication lines 14 and 14′ by way of which the piston operating chambers 10 and 11 are in communication with the receiver units 15 and 15′ (wheel cylinders) of the front wheel brakes 16 and the rear wheel brakes 16′ of the vehicle.
Each communication line 14 or, respectively, 14′ is connected to a line 18 or, respectively 18′ by way of a normally open shut-off valve 17, or respectively 17′, and the lines 18, 18′ are connected via normally open shut off valves 19, 19′ to the receiver units 15 and 15′ respectively.
Furthermore, the connecting lines 14, 14′ are connected by way of normally closed shut off valves 20, 20′ to the lines 21 and respectively 21′, which are in communication, by way of normally closed shut off valves 22, 22′ that are arranged parallel to the valve 19 and, respectively, 19′, with the receiver units 15 and, respectively, 15′. The lines 21, 21′ include one- way valves 23, 23′ which permit only a hydraulic fluid return flow from the receiver units 15 and respectively 15′ when the valves 22 and 22′ are open.
Between the lines 18 and 21 and respectively 18′ and 21 ′ pumps 25 and respectively 25′ driven by electric motors 25 and, respectively, 25′ are arranged together with check valves 26 and respectively, 26′ in such a way that hydraulic fluid can only flow from the line 21 or respectively 21′ to the line 18 or respectively 18′.
Parallel to the shutoff valves 20 and 20′ controllable over-pressure valves 27 and respectively 27′ with serially arranged check valves 28, 28′ are provided such that, with the respective over-pressure valves 27, 27′ opened, hydraulic fluid flow is possible only from the line 14 or, respectively, 14′ to the line 21 or, respectively, 21′.
All the above control valves are operated by an electronic control unit 29. The electronic control unit 29 is connected to a travel distance sensor 30 for determining the actuating position of the brake pedal 1 and/or the pressure sensors 31 for determining a characteristic hydraulic fluid pressure at the output side of the hydraulic actuating unit 2.
Otherwise, the input side of the control unit 29 is connected to wheel sensors of the vehicle which however are not shown but which provide information concerning wheel speed or wheel blockage conditions for the respective wheels.
The system as shown in FIG. 1 operates as follows:
If a fault is detected in the system by the control unit 29 which constantly checks itself for faults, all valves assume the switch positions as shown in FIG. 1 and the electric motors 24 and 24′ of the pumps 25 and 25′ are de-energized. However, this state of the valves and the electric motors may also be present when the brakes 16 and, respectively, 16′ are expected to provide only comparatively small brake forces. If the brake pedal 1 is operated in this state of the system, the pistons 3 and 4 are moved beyond the bores 8 and 9, so that the piston operating chambers 10 and 11 are disconnected from the reservoir 7 and, upon further actuation of the brake pedal 1, hydraulic fluid is directed from the piston operating chambers 10 and 11 into the lines 14 and 14′, respectively of the wheel brakes 16 and 16′ and the brakes are actuated to brake the wheels. As soon as the brake pedal 1 is released, the pistons 3 and 4 and the brake pedal 1 are returned by the springs 5 and 6 to their rest positions in which the receiver unit 15 and 15′ in the switch positions of the valves as shown are in communication with the reservoir 7 and consequently not under pressure. No brake effect is therefore present at the wheel brakes 16 and, respectively 16′.
Under normal operation of the control unit 29, the shutoff valves 17, 17′ are closed when the brake pedal 1 is actuated. Further, the valves 19, 20 and 22 or, respectively, the valves 19′, 20′, and 22′ are in the positions shown in FIG. 1. The over-pressure valves 27 and 27′ are controlled by the control unit 29 depending on the signals of the travel distance sensor 30 and/or the pressure sensor 31, such that, with predetermined controllable pressures in the lines 14 and, respectively, 14′, they are opened and the pumps 25, and respectively, 25′ suck in a certain hydraulic fluid volume by way of the over-pressure valves 27 and, respectively, 27′ from the communication lines 14 and respectively 14′ and supply it, by way of the valves 19 and respectively 27′, from the communication lines 14 and respectively 14′ by way of the valves 19 and respectively 19′ to the receiver units 15 and, respectively 15′ of the wheel brakes 16 and, respectively, 16′ and there, generate a hydraulic pressure depending on the amount of the hydraulic fluid supplied. This hydraulic pressure at the receiver side may be substantially above the hydraulic fluid pressure in the communication lines 14 and, respectively, 14′.
The hydraulic fluid volume which is supplied by the pumps 25, 25′ to the receiver units 15 and 15′ and which determines the hydraulic pressure therein is determined by the overpressure valves 27, and respectively, 27′ whose opening behavior is controlled by the control unit 29. The over-pressure valves 27 and 27′ act with respect to the pump 25 and 25′ like intake throttles.
When, during normal operation, that is, with an operative control unit 29, the brake pedal is released, the valves 22 and 20 and respectively 22′ and 20′ are opened so that the hydraulic fluid can flow back from the receiver units 15 and, respectively, 15′ to the actuating unit 2, wherein possible pressure pulses are attenuated by hydraulic pulsation dampers 32, and respectively, 32′, which are in communication with the outlet side of the valves 22 and respectively 22′.
During normal operation, the pump 25 and respectively 25′ may be constantly energized if, with the brake pedal 1 not actuated, the valves 19 and 22 and, respectively, 19′ and 22′ and/or the valves 17 and 20, and respectively, 17′ and 20′ are constantly open and, accordingly permit hydraulic fluid circulation by the pump 25 and 25′.
In order to make the ABS function possible during braking, that is, in order to cause the release of a braked wheel that has locked, the control unit 29 can selectively open the valves 22 and, respectively, 22′ and, at the same time, the valves 17 and respectively 17′ so that the pump 25 and respectively 25′, can pump hydraulic fluid from the receiver unit 15, 15′ associated with the open valves 22, 22′ back to the actuating unit 2. The valves 22 and 17, and, respectively, 22′ and 17′ are opened in intervals in order to release the respective blocked wheel in intervals in order to then again be able to effectively brake the wheel.
When for an ESP function, a wheel is to be selectively braked (with the brake pedal 1 not actuated), hydraulic fluid is supplied by the respective pump 25 or, respectively 25′ to the respective receiver unit 15 or 15′ of the wheel brakes 16, 16′. To this end, the shut-off valve 20 or, respectively, 20′ and the shut off valves 19, or respectively 19′, associated with the respective receiver unit is opened while at the same time the respective blocking valve 22, 22′ is closed, so that the respective pump 25, 25′ supplies hydraulic fluid to the respective receiver unit 15 or 15′ with a corresponding pressure which subsequently is again reduced by opening of the shutoff valve 22, 22′.
FIG. 2 shows the operational behavior of the brake pressure control arrangement according to the invention.
In the diagram of FIG. 2, the stroke S of the brake pedal, the volume V of the hydraulic medium displaced during brake pedal actuation from the piston operating chambers 10 and 11 and the pressure P in the receiver units as shown depending on the operating force F applied to the brake pedal 1. The values S, V and P are functionally equally dependent on the actuating force F since the stroke S of the pedal 1 correlates vice versa directly to the hydraulic volume displaced by the piston 3 and 4, and the hydraulic fluid volume displaced from the actuating device 2 is reversibly directly related to the pressure P in the receiver units.
During an emergency operation, in accordance with the curve K, a comparatively large brake pedal force F2 is required in order to achieve a pedal stroke S0 or the discharge of a hydraulic fluid volume V0 from the actuating unit or, respectively, to achieve a hydraulic pressure P0 in the receivers.
During normal operation however, the pumps 25 and respectively 25′, assist the transport of hydraulic fluid from the actuating unit 2 to the receiver units 15, 15′ upon actuation of the brake pedal 1, so that a pedal force of only F1 is required to achieve the stroke S0, the receiver unit pressure P0 or, respectively, a displacement movement of the hydraulic volume V0 to the receiver units 15 and 15′ respectively. The curve Ks shows the functional relationship in an exemplary way. The difference F2−F1=Fs represents the power assist effect of the pump 25 and, respectively 25′.

Claims (6)

1. A brake pressure control arrangement for a hydraulic vehicle braking system of a vehicle having wheels with brakes, comprising:
a hydraulic actuating unit (2) actuatable by an operator of the vehicle, receiver units (15, 15′) in communication with the hydraulic actuating unit for operating the brakes (16, 16′) of the wheels, at least one pump unit (25, 25′) connected to the receiver units (15, 15′) via a communication line (18, 18′) including control valves (19, 19′, 22, 22′) for controlling admission of hydraulic fluid to, and its release from, the receiver units (15, 15′), an intake flow control valve (27, 27′) arranged between the actuating unit (2) and the pump unit (25, 25′), the intake flow control valve (27, 27′) being an over-pressure valve subjected to the pressure of the actuating unit (2) in an opening direction and having a controllable opening pressure behavior, and a control unit (29) for controlling the control valves and the intake flow control valve in such a way that, with the actuating unit (2) actuated, in a first operating state, the receiver units are, in intervals, connected only to the suction side of the pump unit (25, 25′) so as to reduce the hydraulic pressure therein, and, in a second operating state, the receiver units (15, 15′) are connected to the pressure side of the pump unit (25, 25′) for supplying pressurized hydraulic fluid to the receiver units (15, 15′) and the pump suction side is in communication with the actuating unit (2) such that the hydraulic fluid volume supplied to the receiver unit is determined solely by the intake flow volume of the receiver unit (15, 15′) as provided by the pump unit (25, 25′) and, with the actuating unit not operated, in a third operating state, the pump unit (25, 25′) is connected with its intake side to the actuating unit and with its pressure side to the receiver unit (15, 15′), and a normally closed shutoff valve (20, 20′), which is arranged parallel to the intake flow control valve (27, 27′) in a circuit branch extending between the actuating unit (2) and the intake side of the pump unit (25, 25′) and which, in the third operating state, is opened by the control unit (29).
2. A brake pressure control arrangement according to claim 1, wherein, in the third operating state, the pump unit (25, 25′) is switchable—in intervals—to its pump-effective operating state.
3. A brake pressure control arrangement according to claim 1, wherein, in the second operating state, the control unit (29) operates depending on the pressure generated by the actuating unit (2).
4. A brake pressure control arrangement according to claim 1, wherein the control unit is effective as a controller providing for operation of the pump unit (25, 25′) and, respectively, the intake flow control valve (27, 27′) depending on a desired and actual value comparison of the receiver side hydraulic pressure, wherein the desired value of the hydraulic fluid pressure is predetermined by an actuating-side operating parameter.
5. A brake pressure control arrangement according to claim 4, wherein the desired value is determined by at least one of an operating stroke length of the actuating unit (2) and an actuating side hydraulic pressure.
6. A brake pressure control arrangement according to claim 1, wherein the pump unit (25, 25′) is combined with control valves (17, 17′ 19, 19′, 20, 20′ 22, 22′, 27, 27′) in such a way that the pump operation is selectively switched between a circulation operation or a pumping operation with a hydraulic fluid supply flow from the actuating unit (2) to the receiver units (15, 15′) and a pump operation with a hydraulic fluid flow from one of the receiver units (15, 15′) to the actuating unit (2).
US11/043,698 2002-07-27 2005-01-26 Brake pressure control arrangement Expired - Fee Related US7264318B2 (en)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
DE10234366.7 2002-07-27
DE10234366A DE10234366B3 (en) 2002-07-27 2002-07-27 Brake pressure control device
PCT/EP2003/007548 WO2004012970A1 (en) 2002-07-27 2003-07-11 Brake-pressure control device

Related Parent Applications (1)

Application Number Title Priority Date Filing Date
PCT/EP2003/007548 Continuation-In-Part WO2004012970A1 (en) 2002-07-27 2003-07-11 Brake-pressure control device

Publications (2)

Publication Number Publication Date
US20050258684A1 US20050258684A1 (en) 2005-11-24
US7264318B2 true US7264318B2 (en) 2007-09-04

Family

ID=31196881

Family Applications (1)

Application Number Title Priority Date Filing Date
US11/043,698 Expired - Fee Related US7264318B2 (en) 2002-07-27 2005-01-26 Brake pressure control arrangement

Country Status (4)

Country Link
US (1) US7264318B2 (en)
EP (1) EP1525127A1 (en)
DE (1) DE10234366B3 (en)
WO (1) WO2004012970A1 (en)

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102011079862A1 (en) * 2011-07-26 2013-01-31 Robert Bosch Gmbh A braking system for a vehicle and method for operating a braking system of a vehicle
JP2015202725A (en) * 2014-04-11 2015-11-16 株式会社デンソー Vehicular brake device
US20180009422A1 (en) * 2015-01-26 2018-01-11 Robert Bosch Gmbh Selective high flow pressure supply for vehicle stability control systems without high pressure accumulators

Citations (21)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5131730A (en) * 1990-06-02 1992-07-21 Robert Bosch Gmbh Hydraulic brake system with anti-skid system and traction control for a vehicle
US5195809A (en) * 1991-02-11 1993-03-23 Alfred Teves Gmbh Hydraulic brake system with devices for controlling both brake slip and traction slip
US5205623A (en) * 1990-11-08 1993-04-27 Robert Bosch Gmbh Hydraulic brake system
US5236256A (en) * 1991-02-28 1993-08-17 Robert Bosch Gmbh Hydraulic brake system, in particular for motor vehicles
US5281012A (en) * 1991-04-16 1994-01-25 Robert Bosch Gmbh Apparatus for distribution of brake force between front and rear axles
WO1994027848A1 (en) 1993-05-28 1994-12-08 Itt Automotive Europe Gmbh Brake system for motor vehicles with a device for adjusting both the brake and drive slip
WO1996010507A1 (en) 1994-09-30 1996-04-11 Itt Automotive Europe Gmbh Hydraulic braking system and pressure-regulating method
DE4438721A1 (en) 1994-10-29 1996-05-02 Teves Gmbh Alfred Hydraulic skid-control braking system for motor vehicle with ASR
DE19501760A1 (en) 1995-01-21 1996-07-25 Bosch Gmbh Robert Method and device for controlling an ABS / ASR system
WO1997010980A1 (en) 1994-09-03 1997-03-27 Itt Automotive Europe Gmbh Externally actuated hydraulic braking system
WO1997047504A1 (en) 1996-06-07 1997-12-18 Robert Bosch Gmbh Hydraulic vehicle braking system with anti-locking and traction control device
EP0841231A2 (en) 1996-11-11 1998-05-13 Denso Corporation Brake control apparatus for a vehicle
WO1998031576A1 (en) 1997-01-15 1998-07-23 Robert Bosch Gmbh Hydraulic brake system
DE19716404C1 (en) 1997-04-18 1998-10-29 Lucas Automotive Gmbh Hydraulic brake system for motor vehicles
DE19756248A1 (en) 1997-12-17 1999-07-01 Lucas Ind Plc Brake booster / master cylinder unit with improved braking ability in the event of a brake booster failure
DE19855667A1 (en) 1997-12-05 1999-08-26 Denso Corp Magnetic valve for vehicle braking system
DE19939437A1 (en) 1999-04-13 2000-10-19 Continental Teves Ag & Co Ohg Hydraulic vehicle brake unit with skid control; has pump to supply hydraulic fluid to brake and pump bypass valve connected in parallel to pump to form independent hydraulic fluid connection
US6142583A (en) * 1996-04-06 2000-11-07 Continental Teves Ag & Co. Ohg Anti-locking hydraulic motor vehicle brake system
US6273525B1 (en) * 1997-03-27 2001-08-14 Robert Bosch Gmbh Method and device for determining a value representing the system pressure in a brake circuit
US6419329B1 (en) * 1997-10-17 2002-07-16 Continental Teves Ag & Co. Ohg Method for improving the control performance of a motor vehicle control system
US6752473B2 (en) * 2002-02-01 2004-06-22 Mando Corporation Electronically controlled brake system for automobiles

Patent Citations (21)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5131730A (en) * 1990-06-02 1992-07-21 Robert Bosch Gmbh Hydraulic brake system with anti-skid system and traction control for a vehicle
US5205623A (en) * 1990-11-08 1993-04-27 Robert Bosch Gmbh Hydraulic brake system
US5195809A (en) * 1991-02-11 1993-03-23 Alfred Teves Gmbh Hydraulic brake system with devices for controlling both brake slip and traction slip
US5236256A (en) * 1991-02-28 1993-08-17 Robert Bosch Gmbh Hydraulic brake system, in particular for motor vehicles
US5281012A (en) * 1991-04-16 1994-01-25 Robert Bosch Gmbh Apparatus for distribution of brake force between front and rear axles
WO1994027848A1 (en) 1993-05-28 1994-12-08 Itt Automotive Europe Gmbh Brake system for motor vehicles with a device for adjusting both the brake and drive slip
WO1997010980A1 (en) 1994-09-03 1997-03-27 Itt Automotive Europe Gmbh Externally actuated hydraulic braking system
WO1996010507A1 (en) 1994-09-30 1996-04-11 Itt Automotive Europe Gmbh Hydraulic braking system and pressure-regulating method
DE4438721A1 (en) 1994-10-29 1996-05-02 Teves Gmbh Alfred Hydraulic skid-control braking system for motor vehicle with ASR
DE19501760A1 (en) 1995-01-21 1996-07-25 Bosch Gmbh Robert Method and device for controlling an ABS / ASR system
US6142583A (en) * 1996-04-06 2000-11-07 Continental Teves Ag & Co. Ohg Anti-locking hydraulic motor vehicle brake system
WO1997047504A1 (en) 1996-06-07 1997-12-18 Robert Bosch Gmbh Hydraulic vehicle braking system with anti-locking and traction control device
EP0841231A2 (en) 1996-11-11 1998-05-13 Denso Corporation Brake control apparatus for a vehicle
WO1998031576A1 (en) 1997-01-15 1998-07-23 Robert Bosch Gmbh Hydraulic brake system
US6273525B1 (en) * 1997-03-27 2001-08-14 Robert Bosch Gmbh Method and device for determining a value representing the system pressure in a brake circuit
DE19716404C1 (en) 1997-04-18 1998-10-29 Lucas Automotive Gmbh Hydraulic brake system for motor vehicles
US6419329B1 (en) * 1997-10-17 2002-07-16 Continental Teves Ag & Co. Ohg Method for improving the control performance of a motor vehicle control system
DE19855667A1 (en) 1997-12-05 1999-08-26 Denso Corp Magnetic valve for vehicle braking system
DE19756248A1 (en) 1997-12-17 1999-07-01 Lucas Ind Plc Brake booster / master cylinder unit with improved braking ability in the event of a brake booster failure
DE19939437A1 (en) 1999-04-13 2000-10-19 Continental Teves Ag & Co Ohg Hydraulic vehicle brake unit with skid control; has pump to supply hydraulic fluid to brake and pump bypass valve connected in parallel to pump to form independent hydraulic fluid connection
US6752473B2 (en) * 2002-02-01 2004-06-22 Mando Corporation Electronically controlled brake system for automobiles

Also Published As

Publication number Publication date
EP1525127A1 (en) 2005-04-27
WO2004012970A1 (en) 2004-02-12
US20050258684A1 (en) 2005-11-24
DE10234366B3 (en) 2004-03-04

Similar Documents

Publication Publication Date Title
US8926027B2 (en) Vehicle braking system
US4578951A (en) Dual-circuit hydraulic brake system
US6899403B2 (en) Braking system having pressure control cylinder whose piston is displaceable by controlled drive source
JP3989956B2 (en) Electronically controllable brake operating device
US5310251A (en) Electro-hydraulic service & parking brake system
US5938297A (en) Method and device for brake application
US20240262330A1 (en) Electric brake system
US5152587A (en) Hydraulic slip-controlled brake system with pneumatic power booster
JPH0781540A (en) Brake pressure and controller in road surface vehicle
JP2675603B2 (en) Automotive wheel slip control device
US6450589B2 (en) Brake pressure transducer for a hydraulic vehicle brake system
US6247762B1 (en) Vehicle braking system with a stroke simulator and a servo device
JPH02171375A (en) Anti-lock braking system with traction slip controller
US7264318B2 (en) Brake pressure control arrangement
US4636008A (en) Anti-skid braking control system
JP2000513299A (en) Hydraulic brake system
JPH04232165A (en) Hydraulic type brake gear
US10173654B2 (en) Electronically slip-controllable vehicle brake system
US20040183367A1 (en) Hydraulic brake apparatus for a vehicle
JP4380512B2 (en) Brake device for vehicle
US6149249A (en) Brake system for vehicle
JP2995968B2 (en) Electronic control brake device
US4717210A (en) Brake-slip-controlled brake system
US20020190571A1 (en) Brake apparatus for a vehicle
JPH04221266A (en) Two circuit type hydraulic brake gear

Legal Events

Date Code Title Description
AS Assignment

Owner name: DALMLERCHRYSLER AG, GERMANY

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:HERP, ANDREAS;SCHOPPER, MICHAEL;REEL/FRAME:016881/0832

Effective date: 20050721

FEPP Fee payment procedure

Free format text: PAYOR NUMBER ASSIGNED (ORIGINAL EVENT CODE: ASPN); ENTITY STATUS OF PATENT OWNER: LARGE ENTITY

AS Assignment

Owner name: DAIMLER AG, GERMANY

Free format text: CHANGE OF NAME;ASSIGNOR:DAIMLERCHRYSLER AG;REEL/FRAME:022846/0912

Effective date: 20071019

Owner name: DAIMLER AG,GERMANY

Free format text: CHANGE OF NAME;ASSIGNOR:DAIMLERCHRYSLER AG;REEL/FRAME:022846/0912

Effective date: 20071019

REMI Maintenance fee reminder mailed
LAPS Lapse for failure to pay maintenance fees
STCH Information on status: patent discontinuation

Free format text: PATENT EXPIRED DUE TO NONPAYMENT OF MAINTENANCE FEES UNDER 37 CFR 1.362

FP Lapsed due to failure to pay maintenance fee

Effective date: 20110904